Content-type: text/html Manpage of lvg

lvg

Section: User Commands (1)
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NAME

lvg - Calculates LVG radiative transfer models.  

PERSON RESPONSIBLE

lgm  

CATEGORIES

models  

DESCRIPTION

LVG calculates a 1-D, 2-D, or 3-D grid of lvg radiative transfer models as specified by the input parameters. When a range of values is specified for a parameter (density, temperature, fractional abundance, column density), models are logrithmically spaced over the interval.  

PARAMETERS

mol
Name of molecule. Known molecules are CO, CS, etc. No Default.
iso
Isotope of molecule if other than main isotopic species. Default is main isotopic species.
den
Density range to be covered by the model grid. Input may be one, two, or three numbers. The first number indicates the number of density models to be calculated; the second and third numbers specify the density of the first and last models in particles/cm3. Models are logrithmically spaced. If only two numbers are given, the density for all models is set to the second number. If only one number is given, the default density is assumed. Example: den = 5,1.0e4,1.0e6 -- 5 models with densities from 1.0e4 to 1.0e6. Defaults = 1,10000.
xmol
Range of fractional abundance of molecule to be used in calculation. Input may be one, two, or three numbers as above. WARNING -- xmol and cd can not be non-zero simultaneously. Default = 0,1.0e-8
cd
Range in molecular column density to be used in calculation. Input may be one, two, or three numbers; see description of density for more format information. WARNING -- xmol and cd can not be non-zero simultaneously. Default = 1,1.0e12.
tk
Range of kinetic temperature to be used in calculating models. Input may be one, two, or three numbers; see description of density for more format information. Default = 1,20
dv
Velocity FWHM of line in km/sec. CD will be divided by this value for calculating the radiative excitation.
iter
Maximum number of iterations allowed for each model. Usually the defaults is fine but models with high opacity and low density may require more iterations. Default = 25.
tbkg
Blackbody temperature for background radiation field in all transitions. Normally set to the cosmic background temperature. Default = 2.78.
pops
Data file name for level populations. Two or three of den, xmol, cd, or tk must be specified with more than 1 model along that axis. If no name is given, no file will be written. Default: ' '
trads
Data file name for line radiation temperatures. Two of den, xmol, cd, or tk must be specified with more than 1 model along that axis. If no name is given, no file will be written. Default: ' '
trans
List of frequencies (in GHz) of transitions to be included in 'trads' file. If none are specified, 20 transitions are selected. If there are more than 20 possible transitions, the first 20 with frequencies between 70 GHz and 500 GHz are selected. No more than 20 transitions may be written. Default: program selects 20 transitions.
print
Parameter which control level of printed output.
   0 = minimum output which is useful when running grids
   1 = normal output level
   2 = detailed output level - used for debugging and error checking
log
Name of log file were full printed output for human consumption is written.


 

Index

NAME
PERSON RESPONSIBLE
CATEGORIES
DESCRIPTION
PARAMETERS

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Time: 18:35:38 GMT, July 05, 2011